Abrasive disk backup pad



' 1951 F. DE MICHEL ABRASIVE DISK BACKUP PAD 2 Sl-IEETSSHEET 1 Filed June 3, 1948 ii? I J Oct. 30, 1951 FfDE MICHEL 2,573,411

ABRASIVE DISK BACKUP PAD Filed June 3, 1948 2 SHEETS-SHEET 2 Patented Oct. 30, 1951 ENT OFFICE ABRASIVE DISK BACKUP PAD Frank De Michel, Chicago, Ill. Application June s, 1948, Serial No. 30,897

My invention relates to an improvement in abrasive disk backup pads-and more specifically to a pad which is air cooled and may be consid- 4 Claims. (01. 51197) ered an improvement over the pad disclosed in my copending application, Serial No. 791,301, filed December 12, 1947. g

" One object of my invention is to provide an improved backup pad which will'minimize the accumulation of frictional'heat.

Another object of my invention is to provide a novel, flexible backup pad making provision for cooling its associated sandpaper.

Still another object is to provide a backup pad in which the stiifening members are incorporated in a novel and improved fashion.

Yet anotherobject is to provides. novel device erably made of metal, fiber or phenolic material. Each of these sheets is punched to provide a plurality of perforations 30 therein arranged in regular order and the sheets are then stacked in a shallow conical arrangement. Rubber laminations 32 are interspersed between the members of the stack and a coating of tough heat-resistant rubber is molded thereabout, the heat and pressure of the molding being suflicient to bond the coating and the laminations to the stacked sheets and to link the laminations through the consisting of a backup pad which incorporates secondary mounting means to permit easy removal from the driving spindle for substitution thereof and yet which is retained on the spindle sufliciently strong to facilitate the changing of 1 of the edge of the sidered as being taken substantially along the line 3--3 of Fig. 1 looking in the direction of the arrows;

Fig. 4 is a plan view of the under side of the central portion of the pad showing the hub and the plate structure immediately surrounding it;

Fig. 5 is a plan view of one of the stiffening laminations incorporated inthe plate; and

Fig. 6 is a perspective view of the type of bolt employed in the practice of my invention.

In its preferred embodiment, my invention comprises a hub l0 having a threaded opening I 2 extending therethrough which is adapted to be mounted on the threaded end I4 of a rotable power driven shaft IS. The outer surface of the hub is flared outwardly and upwardly to provide a flange l8 offering a large diameter supporting surface 20 for the plate 26. A cylindrical projection 22 concentric with the shaft opening and slightly spaced therefromextends upwardly from thesurface 20. Outside theprojection is a ring of tapped holes 24 extending through the flange I8 to open on either side thereof.

The plate 26 comprises a plurality of flexible, thin circular sheets 28 of varying diameter, prefperforations 30. In this fashion a plate of controlled flexibility is obtained in which the supporting members are firmly integrated with the whole. The plate is drilled to provide a central opening 36, whereby the plate may be mounted on the projection 22 of the hub, and a plurality of ports 38 annularly surrounding the central opening to align with the tapped holes 24 in the hub when the plate is mounted thereon.

In the molding process, the face of the plate is formed to provide a central recessed portion 40 intended to accommodate the nut 42 so that it may be flush with or below the surface of the face. In this depressed portion a solid annulus 44 immediately surrounds the opening 36 which is bounded on its outer edge by a passage 46 passing through the centers of the ports 38 concentric with the ports. The rubber is removed from the surface of the upper sheet to provide bolt head seats 48, the diameter of the rubber removal being greater than that of the bolt head. Outwardly of the passage 46 a plurality of outwardly directed ribs 50 is formed, the outer portions 52 of which lie at the face level and the inner ends 54 of which are inclined downward to the level of the depressed portion 40. Outwardly of these ribs is located an outer passage 56 and outwardly of the passage lies a second series of ribs 58 terminating on the outer edge of the plate. These ribs and annular passages form a system of intercommunicating, generally radial, closely spaced passages 6|] extending from the holes 38 to the periphery of the plate. s

The coating on the underside of the plate is molded to provide an integral mounting ring 62 which consists of an annular protrusion 64 and a lip 66 extending inward from the top of the protrusion. The inside diameter of the protrusion is slightly larger than and the inside diameter of the lip smaller than the hub flange l8,

such that the ring may be slipped over the flange to provide a loose and easily detached secondary mounting means for a purpose to be subsequently described.

The type of bolt 68 preferably employed to seth po sil may beplacedin all or some of the accommodat n h es... wo. h tswould b the. i mum co on ntwi -pre rv n th ba an f th had.- T hub. n nrcase, is thre de o th .shaftand theplate.S-eate. onthe hub. Align- .ment of the ports and holes is accomplished by the bolts or by manual orientation.

The sandpaper disk B 2 ,to beempIOyed with 3 cure the plate to the hub is illustrated in Fig. 6. It is characterized by a head 10 having cross slots 12 thereon and a hole 14 extending axially throughout the length of the shaft 16. The shaft is externally threaded to seat in the tapped holes 24 of the hub.

The nut 42 is the type conventionally employed in abrasivefdi'skibackup pads f'and consists of. a short tubular secationl8 threaded on its inner surfaces to co-operate with the threaded shaft H and having a wide annular flange 80 formed on the upper end thereof.

In use the plate may or may not :be bolted to the hub depending on whether it is" anticipate W ed that the pad will be changed irequently ior example, to mount a plate of aiisuiersrze. The advantage in usin the bolts, of coursefis'tojinsure correct alignment Iof the hub holes 24 and If bolts areto be employed they this pad is of theeOnventional type having. an

axialhole thereinadapted to. fit closely. about theshaft IQ of the nut. lIt will usuallybe fitted to thenut and the nut then screwed down on .thethr ded s aitend. Lluntil. the paper is .firmly secured between the nut flange 80 on one side and the ring 44 and inner rib,ends...54 on the other. .It will benoted that. theplateis thus locked in the assembly whether or not the boltsare employed As power is applied to the shaft. and. the .disk brought to sanding velocity, centrifugal force iihparted to the air in the passages 60 on the te t o t e ad.. ta t e. a flow throu h thep Air enters the passages atth inner.v ends thereof through the hollow bolts fi8, or, where .bolts are not used, through the bolt holes 24 and .ports 38 in the hub andplate, passesthroughthe slots 12, 1 theIboltfheads into the annulanspacetd provided between the bolt head andthe oversized bolt headseat 48 and thenceinto theannular passage .and.... adia1 passages 60 to expulsion from the periphery, offlthepad. m the event that two or three, boltsonly are employed to secure thehub and. plate together, conventional bolts will, serve, the unusedbolt holes providing the air; intake.

fllhe mounting ring fig. is. oi importance when the work bein performed.involveschanging of plates, in which situationtheplateis notbolted to the hub. When the abrasive disk. needsreplacement, the removal of the nut would normally result in the plate fallingofi thelhub. or, at least, making ,retentionthereon diflicult and disk replacement awkward. The, mountin ring serves as a loose connection between thetwo ineiiibers whereby the plate is retained in position on the hub despite the removal of thenut. jOn the/other hand, the lip dithering is sufliciently, resilient and overlaps the flange of the hub sufiiciently slightlyso that the plate may easily be separated from or installed on the hub.

"Having described my invention, what I claim as ito open to the periphery thereof, said plate and saidhuh having a plurality of aligned ports therethrbli'g'hboinmunicating with the inner end of ..ssaid;; passages, and tubular securing members a flexible heat resfi ntgcoating flmoldedabout said. stack, and" or' rhii 1'g,.'6pehings'throj gh said padto' ofieratively said pad to a pow-- cred. shaft. a

' 3. A 'e'xibl'abrasiv disk is" his bad tastes to have"an"abras' 'ldiskgrholinted on thejface; thereof. comprising. a .Iplurality .of resilient cir-- 'e' e i ee ej e nt ;eif r ne;dieieeter J e. rittilln ithetfihe m nt-9 e st i d eeee the a e. Qi. ai 'padfahd the Ye liggelen 'ents are stacked in the olden of? dimnis j ng diameter away from said race, "each of said'elnients being oo mprised ,of .one,,. or .more resilient, thin, dimensionally j st'able, 4 fencing-i, eparated ilates. rubber-lilm interleaving separa ing. gall I the plates said stack .bonded togetheri'through the perforations ini'saidi plates, ,a'flex'ible heat resistant oating for said stack" molded 'thereabout to gontainsaid stack and to unite with the interleaving through the perforations 'in"the"outer'plates, and means forming openings through saidpad to link operativelysaicl'pad toajpo'werdshaftv .4. In aplate for, anabras'ye di k backup pad adapted 'to be new" on a" powered spindle by retentionbetween ahub on the underside thereof and". affsandpaper. nut ion the face thereof, ,a th n n -i b e eev et tencl ne f' e si jie tme r e fi the unde dogs: saidp a e ooniorrned to engage the adjacenflpe'ripheryoisaidhub V FRANK DE MICHEL.

.ffii F l ifi C v '-Q'Ilhekiollowing references are of record in the .file'of thi pa entz UNITED STATES PATENTS 

